add CHANGELOG.md

Signed-off-by: Amit Galitzky <[email protected]>

Author: amitgalitz

CHANGELOG.md

@@ -9,6 +9,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.1.0/)
 - Adds capability to automatically switch to old access-control if model-group is excluded from protected resources setting ([#1569](https://github.com/opensearch-project/anomaly-detection/pull/1569))
 - Adding suggest and validate transport actions to node client ([#1605](https://github.com/opensearch-project/anomaly-detection/pull/1605))
 - Adding auto create as an optional field on detectors ([#1602](https://github.com/opensearch-project/anomaly-detection/pull/1602))
+- Adding create and start to AD node client ([#1611](https://github.com/opensearch-project/anomaly-detection/pull/1611))
 
 ### Bug Fixes